Field of the Invention
The present invention relates to a combustion apparatus and a method of forcibly circulating a heating medium in a combustion apparatus.
There have been known methods of combustion and combustion apparatuses in which a heating medium such as sand, gravel contained in a combustion chamber is mixed with fuel and the fuel is fired.
According to the invention, a combustion apparatus includes a combustion chamber, a particulate heating medium in the combustion chamber and conduit means having a nozzle for feeding upwardly into the combustion chamber a combustion gas, whereby the heating medium is circulated in the combustion chamber. An intake port communicates a lower portion of the combustion chamber with a portion of the conduit means upstream of the nozzle. The intake port extends into a bottom of the combustion chamber. Pressure reducing means are associated with a junction of the intake port and the conduit means and induce the heating medium to flow into the intake port. In one embodiment, the pressure reducing means is in the form of a reduction in the sectional area of the conduit means adjacent to the junction. In another embodiment, the pressure reducing means is in the form of a nozzle.
A fuel supplying pipe has an end introduced into the intake port for inducing the heating medium to flow into the intake port at a rate proportional to that of the fuel. The fuel supplying pipe preferably extends downward toward the end thereof in a vertically extending portion of the intake port. Separate means may be provided for supplying fuel to the combustion chamber and a separate burner for heating the combustion chamber may be provided.